Gear mounting



Feb. 6, 1940. L. R. BucKENDALE GEAR MOUNTING 2 sneets-sheet' 1 Filed Aug. 6, 1936 Feb. 6, 1940. L. R. BucKENDALE 2,189100 GEAR MOUNTING Filed Aug. 6, 1936 2 Sheets-Shee'c 2 Patented Febf ;1940 V aisaroo.

i 'GEAR-MoUN'rrNG Lawrence Ray Buckendalal etroit, Mich., assign-h``` i or to The Timken-Detroit Aozle Company, Detroit, Michl., a corporationofjOhio i ppcanhugust 6, 1936; serial Nd. 94,885' o W 2 oiaims. (ciast- 52.05)

This invention relates tofi gear mountings and it is rnore partioularly concerned with the mounting of bevel gearsin the drive axle assemblies of automotive Vehicles, altho'ugh it is not limited to such use. i I f The most common methcdjof attaching a gear to 4its mounting member atthe present time is what may be terrned the rivet lmounting. This consists of press-fitting the gear onto a pilot surface of the mountingmember With its bach surface abutting a flange formed on the` mounting member.` A series of aligned lrivet holes are located in the gear andythe flange. 'Ifhe rivets may be heated before insertionbut are usually inserted "cold and when they are headed over they: expand or f'swell in their `mid-scction and` substantially completely fill their apertures.

This mounting is satisfactoryin some respects b'ut it possesses several 'disadvantageswhch the present invention is 'designed to overcome;l

Vith the production methods now in'use it is practically impossible to provide a series of openings in the gear that will precisely' register with v a series of openings in the flange, 'with the result that in some instances the e-ntire ``gear driving torque is taken by one or two rivets;l and failure discussed old type of gear mounting it has been proposed to provide the gear and mounting member with intermeshing splines, in 'order to relieve I the rivets of at'least some 'of the torque'load. The splinevmountingvrepresents a considerable advance over the plain rivet mountingbut`` it :is not `completely satisfactory because the distance of the splines from the axis 'is so small that the splines often fail in service.` i

Another factor which has militated against the success of certain spline mountings heretofore proposed resides in the factpl'that the rivets are located a greater .distance from the axis than the `splines, with the result that a given amount of looseness in the splines'is refiected v"as a greater` e amount of looseness at therivets, which naturally` imposes thetorque load upon the rvets and' defeat'sthe primary objectivefof the spline rnount-` rigidly maintain the gear in properassembled' position at' a1l` times,'w hich Will positively eliminate backlash and which Willreenforce the gear against distortion in response to the abnormall high pressures or thrusts encountered' in lsever'e service. 3

Another important object is to provide a"gear mounting embodying a piloting surface formaintaining concentricity of the gear and plurality of splinesrof considerable size and disposed' a comparatively great clistance from the: gear axis to adequatelyntransmit the torque loadvfron'i'the `gear to the mounting. o A further object is to provide; a gearmounting embodying av piloting surface for inaintaining surface and also adequately transmit the'torque of the load between'the gear and the mounting Without loacklash. i i

having a continuous spline connection` located outwardly of the 'rivets or screws which secure the parts together, ``thereby `insuring all'joffi` vthe torque loadwillbe t-akenlby the splin'es.A i

i `There have recently gone' into use .Vehicles ofthe rearmotored type. In some of these vehicles the 'motor` is' located rearwardly of the rear vaxle and is coupled to the rear axle byrmeans of a comparatively short propellerfshaftwhich is 'disposed at'an acute angle with respect` t'o'ithe rear axle. `Thisnecessitates'locating'the drive`` lpinion at an acuteangle with respect to the axis i of'the ring gear and it hasbeenfound that, the;`

` ring gear is subjected toy forces that renderconventional mountings incapab-leof securelyimaintaining the gearin place. n i ;o `It ,is accordingly a further object of. theynvention to provide a mounting' assembly for` se- [O curely holding the ring gear in place' which is' particularly valuablefi in 'a gearilorganization of. the Character wherein the axes of the pinion and ringgear are disposed at anlacute angle`withr}espect to eachiother. i

Further objects will become apparent as the specification proceeds in connection with the 'an-i n nexed `drawings,` and fromthe appendedjclaims. Inthedrawings: 1 f z iFigure 1 is a side elevationalpview of a gear inounting embodying the invention, andfthegear i Figure 2 is a fragmental view of 'the' mounting mernber v emnloyedj` in Y:the

longitudinalisectional Sdevice of Fgure 1, and is taken substantially along the; line 2' 2 of Figure 3.

F'igurev 3 is an endA elevational view of the' pears when viewed from the right-hand side of Figure 5 is an end elevational view of. the gear of Figure 4 as it appears when viewed from the right-hand side of that figure, and

FigureG is a longitudinal sectional view of a modified form of gear mounting also forming part of the invention and illustrates the ring gear and pinion, in cooperative meshing relationship.

WithA continued reference to the drawings, wherein like reference characters have been employed to designate like parts throughout the severalviews thereof, the gear supporting member Ill of the invention is illustrated as constituting one section of 'a dilferential casing for the driving axle of an automotive vehicle, but it is to be understood that the mounting member is not limited to this form.

Mounting member EU is journaled for rotation inwell known manner (not shown) Vand is provided with a plurality of semi-cylindrical recesses I l in lwhich the' diffierential Spider may be mountedj a plurality oftapped recesses 12 for receiving the ends of cap screws which hold Athe other difierential casing section (not shown)` in place'; a cylindrical portion 53 through which one of the driving axles may extend; and an outwardlyy facing cylindrical surface lf'i upon which one of the supporting bearings may be mounted. I

The mounting member is also provided with an accurately lformed cylindrical piloting surface l of predetermined diameter and a radially disposed fiange 16 having a hacking surface. H. Flange. E3 is reenforced against distortion response to gear thrust forces by a plurality of integrally provided with accurately formed splines iii, which are preferably of involute form and terminate short of surface l'l'for a purpose that Will presently appear.V Flange IB isl also provided with a plurality of preferably symmetrically located openings 2| for accommodating the lrivets or other gear securing means.

The bevel gear 22, to which the invention'has been applied, is provided with the usual'bevel teeth `23 and a smooth back surface 213. The gear is provided with a flange 25 having a plurality of openings 2i therein which are preferablylcounterboredf to accommodate the rivet heads. I Openings 26- are formed so asto register as closely as possible with openings 2| of mounting member Hi.

Flange 25 terminates in an accurately formed inwardly facing pilot surface 21 which'cooperates with pilot surface Hi of member-HI. Formed in gear 22 adjacent fiange 25 are a plurality of in-' wardly facing splines 28 which are preferably' of involute form and are so dimension'ed as to closely interlock lwith splines l9 of the mounting member whenthefparts are assembled.

Beforesplines 28 are formed a groove 28 is preferablyformed in the gear so the splines may be cutto full depth Vthroughout their length; Groove 29 also provides an annular'pocket into which any burrs, which mayv be pushed up from the splines when the parts are assefnbled, may be 'deposited Otherwise, small bits ,of metal might get between the flan'ges on the gear and lmounting. and prevent the two partsfrom being have been assembled the piloting surfacesv fit snugly without lost motion so that they restrain gear 22 against radial movement with respect to the mounting and'thereb'y maintain the parts concentric ,at all times.

The splines also fit tightly with the result that in addition to relieving the rivets of load by taking all of the torque load between the gear and the mounting, they also function as secondary piloting surfaces and assist in restraining gear 22 against radial movement with respect to the mounting. w

For instance, when `gearflZ is driven byl a bevel pinion and is transmitting power thrust forces of considerahle magnitnde are developed in the gear and they maybe resolved into axial components and radial components. The axial components are absorbed by hacking surface ll I which restrains the gear against deforming in an axial direction. The radial component may be divided into two parts' one is absorbed by piloting surface S5 and. the other is absorbed by the splines which fit tightly and constitute secondary piloting surfaces.

splines ll and 28 are particularly well a'dapted to performvthis function as they are located opposite the tooth pressurevcentre of the gear, i` e., they are so located that they will be intersected by lines drawn normal to the bevel gear teeth 23 at points approximatelyl midway between the tooth ends.`

Splines iii, by reason of their location at the periphery of fiange S6, possesses several advantages. In the first place they are located a maximum distance 'from the axis of the mounting and possess torque arms of maximum length, with the resultl that for splines of a given size the shearing stresses exerted upon the spline teeth are of a minimum value. I b

By locating the splines a greater distance from the axis a greater number of splines may be used and they may also be made of greater circumferential thickness to more readily resist the shearing stresses to which theyare subjected in service. v

Also the splines are located outwardly of the rivets, with the result that should any lost motion develop between the splines they will permit considerably less ang'ular movement between the gear and the mounting than they would if they were disposed inwarly of the rivet connection. This feature insures that any lost motion in `the splines will not result in placing the rivets under load, the latter being designed to simply lock the parts together in an axial direction and not to transmit torque. Another advantage of locating the splines'on the periphery of the vflange resides in the fact that they may be hobbed rather than shaped, which cuts production costs.

vBy way of simplifying the disclosure as to the clearavnces provided between the various parts it Amight be pointed out that theoretically the pilot surfaces and the splines would be perfect circles. If it were possible to achieve this in practice the best procedure would be to have only a very slight tolerance on the piloting surfaces and'a drive fit on the splines in order that they might carry all the torque. i i i Because of machining errors the next best practice is adopted, namely, to machine the piloting surfaces line in line about A.004; of an inch loose. In machining the piloting surfaces and in forming the splines, slight errors are foundito enter almost always, with the resultithat the parts may have a line in line fit 'on one side of the periphery of the piloting surfaces and a necessarily looser fit on the other side. In this way, while the splines have a force fit and tightly interlock, they do not at any time have to be driven or jammed together.

Involute splines are ofpartioular value vin my gear mounting as it is possible to makethem fit very closely and yet not so tightly as to require a drive fit." This is possible by reason of the tapered surfaces of the .teeth which when forced together exert a wedging actionupon each other.

I have accordingly provided a gear mounting which overcomes all of the disadvantages of the prior art and rigidly holds the gear in place in` concentric relationship to its mounting without any backlash whatever, and is so designed as to offer considerable support for the gear, thus adequately resisting distorting tendencies set uptin the gear during operation. i

Although I have described rivets 3| as having a tight fit in openings Zi and 26, it is to be under-c,

stood that if desired openings 2! or 26 may be' made oversize, so as to provide some degree of i lost motion radially between one of the members and the rivets or screws or other fastening means because the splines transmit the entire torque load. The appended claims are intended to embrace my invention when it assumes thisform.

In Figure 6 I have shown another form of gear mounting embodied in a gearassembly of a particular character as it is partieularly equipped to resist the forces developed during operation thereof, but it is to be understood that it is not flange 54 having a clamping surface 55 and the fiange is provided on v``its periphery with a plurality of involute splines 56, as in the first form of my invention. Located adjacent fiange 54 is a cylindrical piloting surface 51.

Surrounding supporting member 55 is a beve i ring gear 58 having bevel teeth 59; a hacking surface Si; a pilot surface 62; and a plurality of involute splines 53, which are spaced from the' gear flange by an annular groove 64.

Gear 58 is assemb-led with mounting member 50 with their eomplemental parts in contact in the same manner as the gear of the first form of the invention and with approximately the same clearances. The gear may be held in place by any suitable means, as for instance, a plurality of bolts 66 which pass through aligned apertures i in the gear and mountng member. The heads of bolts 66 are each provided with a fiat side 61 which cooperates with an abutment surface 68 on member 50 to restrain thebolts against rotation when the parts are pulled home by nuts 69.

'I'he ring gear meshes with a drive pinion ,Tlc

which is mounted for rotation in bearngs 12 and The carrier i or gear` the'axis of rotation'm of the pinion is disposed atan acute angle with respect to the axis ofthe pinion. The specific construction of the carrier, the bearing assemblies andithe casingwill constitute the subjectof a separate application and 13 carried by casing 53, and as seen in Figure '6V f they will, therefore, notbe described in greater detail herein. i i i `It is accordingly seen that the relationship of the hacking surface `and the: piloting surface are reversed with respect to the corresponding parts of the gear mountingshown in Figures 1 to 5 inclusive, and it has been found thatthis 'assembly p is peculiarly adapted to resist the thrust lforces set up in the gear assembly shownin Fig-` whereas the radial component is absorbed by piloting surface 51. Also, splines 56 and 63 constitute secondary piloting surfaces for restraining the gear against radial movement with respect to its lmounting member, in a manner similar to that described in connection with the first form of the invention.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing dei, scription, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What isclaimed and desired to be secured by United States Letters Patent is:

1. In a gear mounting, a gear supporting member having a radially extending fiange, said 15 ure 6. For instance, the axial component of the i gear thrust is resisted by hacking surface 6|,`

fiange being provided `onione side with a backing surface and having a plurality of spline titeeth on its periphery, said member also having a portionproviding a smooth, substantially cylindrical, outwardly facing piloting surface axially offset to one side of said fiange and adjacent 1to said hacking surface, said piloting surface having a diameter which-is materially smaller than that of the periphery of said flange; a bevel` and said supporting member flange arranged inwardly a substantial distance from the periphery `member having a radially extending fiange, said ``flange being provided on one side with a backing surface and having a plurality of spline teethion its periphery, said member also having a portion providing a smooth, substantially cylindrical, outwardly facing piloting surface axially offset to one side of said flange and adjacent to said hacking surface, said piloting surface than that of the periphery of said fian'ge; a bevel gear having bevel teeth facing outwardly and away from said hacking surface and an inWardIy projecting radial fiange seated on said hacking ysurface and provided at its inner edge With a cylindrical surface closely fitting over said. piloting surface of said member; a plurality of algned apertures in said gear fiange and said supporting member fiange arranged inwardly a substantial distance from the periphery of said supporting member fiange; and securing means extending through, and snugly fittingl in, said apertures; saidrgear being also provided With a plurality of internal spiine teeth interlocked with the spline Vhaving a diameter which is materially .smaller assist in supporting said gear against radial 10 loads, back up said bevel gear opposite its center of' pressure, and assume all torque Stress in said mounting.

LAWRENCE RAY BUCKENDALE. 15 

